Valve for rock drills



1932- w. A. SMITH, JR 1,343,953

VALVE FOR-ROCK mums Filed Dec. 23, 1929.

GHQ-2 "222i m' z'i'zzzzk H154 110mm.

Patented Feb. 9, 1932 PATENT orrlcs WILLIAM A. SMITH, 33., 0F PHILLIPSBURG, NEW JERSEY, ASSIGNOR TO INGERSOLL- RAND COMPANY; OF JERSEY CITY, NEW JERSEY, A. CORPORATION OF NEW JERSEY VALVE FOE DRILLS Application filed December 23; 1929. V Serial No. 4163138.

This invention relates to rock drills, but more particularly to a distributing valve for fluid actuated rock drills of the hammer type.

A few of the objects are to obtain a rapid and positive action of the valve and to assure a heavy blow of the hammer piston against the workin implement.

Other obgects will be in part obvious and in part pointed out hereinafter.

In the accompanying drawings illustrating the invention and in which similar reference characters refer to similar parts,

Figure 1 is a sectional elevation of a rock drill constructed in accordance with the practice of the invention and showing the valve 7 in'the position which it will assume at the beginning of the working stroke of the piston an Figure 2 is a similar view showing the valve in the reverse position.

Referring more particularly to the drawings, A designates a cylinder having a piston chamber B in which is disposed a reciprocatory hammer piston C. The cylinder A has a free exhaust port D which is controlled by the piston C. f

A closure is provided for the frontend of the piston chamber B in the form of a front cylinder washer E which also serves to centralize a front head F with respect to the cylinder A. 7

In the front head F is a bore G to receive the shank of a working implement H which extends into a cavity J in the back head F to receive the blows of the hammer piston C. Such blows are in this instance transmitted to the working implement H by an anvil block K disposed slidably in the front cylinder washer E. 1

In the rear end of the cylinder A is a valve chest L comprising a pair of plates 0 and P. The plate 0 is seated adjacent the rear end of the piston chamber B for which it'forms a closure and supports the plate P. Seated upon the plate P is a back head Q which S into which pressure fluid may be constantly admitted from a suitable source of supply.

In the wall of the throttle valve R is a port .1 to register-with a passage U in the back head Q and which passage opens into a supply reservoir V also in the back head Q.

Within the plate P is a bore to form a valve chamber W adapted to accommodate a distributing valve X for which the plate 0 forms a seat. The valve chamber W comprises an enlarged portion Y and a reduced portion Z. The pressure fluid intended to be distributed by the valve X is in this instance introduced into the enlarged portion Y and vconveyed thereto by a supply passage b which communicates with the supply reservoir l/ At the juncture of the enlarged portion Y and the reduced portion Z of the valve chamber W is an annular groove 0 from which leads afront inlet passage d having its outlet opening at the front end of the piston chamber B. The pressure fluid utilized for driving the piston C forwardly against the.

anvil block K is admitted into the rear end of the piston chamber B by rear inlet passages e inthe plate 0. v

The valve X comprises a stem f which extends slidably into the reduced portion Z and a flange g at the front end of the stem lies within the erarged portion Y and is preferably of somewhat smaller diameter than said enlarged portion so that the pressure fluid will flow over the edge of the flange to the rear inlet passage e.

The front end of the flange g constitutes a pressure surface it which is intermittently exposed to. compression from the rear end of the piston chamber B for throwin the valve X rearwardly. On the rear end 0 the flange g is a constant pressure surfacej of smaller area than the pressure surface it and against which pressure fluid constantly acts to throw the valve forwardly.

Additional means are provided to assist in throwing the valve forwardly. To this end the stem f of the valve is provided with an actuating and holdin surface k which is intermittently expose to pressure fluid to assist the pressure acting against the pressure surface to throw the valve forwardly. The

pressure fluid'utilized for this purpose is portion Z of-the valve chamber b a passage 0 which communicates at its in ct opening with the inlet passage (1.

In order that the piston C may strike a heavy blow against the anvil block K and thus to the working implementH unhampered by compression in the front end of the piston chamber B, the valve stem f is provided with a reduced portion or neck 1) around which compression may flow from the front inlet passage d to a vent 9' leading from a point intermediate the ends of the reduced portion Z to the atmosphere.

The operation of the device is as follows: With the valve X and the cylinder A in the rearmost ositions illustrated in Figure 1, pressure uid entering the enlarged portion Y of the valve chamber W from the supply passage 6 will flow over the edge of the flange 9 through the front end of the valve chamber and through the rear inlet passages e into the rear end of the piston chamber B to drive the piston C forwardly against the anvil block K. Shortly after the piston C starts on its forward stroke, it will cover the exhaust port D and the air in the front end of the piston chamber B will then be expelled therefrom through the inlet passage d and around the neck p of the valve, thence through the vent g to the atmosphere. In this way'a heavy uncushioned blow will be struck by the piston against the anvil block.

Shortly prior to the impact of the hammer piston 0 against the anvil block the rear end of the iston C will uncover the exhaust port D so that the pressure fluid utilized for impelling the piston C forwardly will be exforwardly;

hausted to the atmosphere. This will cause a drop in pressure forwardly of the pressure surface .h. The pressure acting against the pressure surface j will then start the valve Upon the unseating of the valve pressure fluid will flow' into the inlet passage (1 and thus also through the passage 0 into the rear end of the reduced portion Z of the valve chamber. There it will act against the surface In to' assist the pressure fluid acting against the pressure surface j to complete the forward movement of the valve X and also to hold the valve in its foremost position.

and rear inlet passages leading from thethe cylinder to throw the valve for opening the rear inlet passage, a constant pressure surface on the other end of the flan e constantly exposed to pressure fluid ten ing to throw the valve for opening the front inlet passage, an actuating surface on the stem, and a passage in the valvechest for intermittently conveying pressure fluid from the front inlet passage to the actuating surface to assist the pressure fluid actin against the constant pressure surface in t rowing the valve and to hold the valve momentarily stationary.

2. In a fluid actuated rock drill, the combination of a cylinder and a piston therein, a valve chest having a valve chamber, front and rear inletpassages leading from the valve chamber to the ends of the cylinder, a distributing valve in the valve chamber to control the inlet passages and comprising a stem, a flange on the stem to control the inlet passages and around which pressure fluid flows to the rear inlet passage, a pressure surface on the flange intermittently exposed to compression from the rear end of the cylinder to throw the valve for opening the rear inlet passage, a constant pressure surface on the other end of the Hang: posed to pressure fluid ten 'n to throw the valve for opening the front in ct passage, an actuating surface on the stem, a passage in the valve-chest for intermittently conveying pressure fluid from the front inlet passage to the actuating surface to assist the pressure fluid acting against the constant pressure surface in throwin the valve and to hold the valve, a vent lea g from the valve chamber to the atmosphere, and a neck on the stem around which compression flows from the front inlet passage to the vent.

The pressure fluid thus admitted into the front end of the iston chamber will return the piston 0. he air in the rear end of the piston chamber B will then be compressed by the piston and such compressionwill act against the pressure surface It to raise the valve -X again to its initial position, thus completing the cycle of operations.

I claim:

1. In a 'fluid actuated rock the com i bination of. a cylinder and a pistontherein, a valve chest having a valve chamber, front constantly ex- 

